diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/psi/JetPsiUtil.java b/compiler/frontend/src/org/jetbrains/jet/lang/psi/JetPsiUtil.java
index 525be31df08..7336820ded1 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/psi/JetPsiUtil.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/psi/JetPsiUtil.java
@@ -128,18 +128,24 @@ public class JetPsiUtil {
         return getFQName(file.getNamespaceHeader());
     }
 
-    public static String getFQName(JetClass jetClass) {
+    public static String getFQName(JetClassOrObject jetClass) {
         PsiElement parent = jetClass.getParent();
         if (parent instanceof JetFile) {
             return makeFQName(getFQName((JetFile) parent), jetClass);
         }
-        if (parent instanceof JetClass) {
-            return makeFQName(getFQName(((JetClass) parent)), jetClass);
+        while (parent instanceof JetClassBody) {
+            parent = parent.getParent();
+            if (parent instanceof JetObjectDeclaration && parent.getParent() instanceof JetClassObject) {
+                parent = parent.getParent().getParent();
+            }
+        }
+        if (parent instanceof JetClassOrObject) {
+            return makeFQName(getFQName(((JetClassOrObject) parent)), jetClass);
         }
         return jetClass.getName();
     }
 
-    private static String makeFQName(String prefix, JetClass jetClass) {
-        return (prefix.length() == 0 ? "" : prefix + ".") + jetClass.getName();
+    private static String makeFQName(String prefix, JetClassOrObject jetClass) {
+        return ((prefix == null || prefix.length() == 0) ? "" : prefix + ".") + jetClass.getName();
     }
 }
diff --git a/compiler/testData/diagnostics/tests/scopes/kt900.jet b/compiler/testData/diagnostics/tests/scopes/kt900.jet
new file mode 100644
index 00000000000..ab9cd880977
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/scopes/kt900.jet
@@ -0,0 +1,69 @@
+//FILE:a.kt
+//KT-900 Inaccessible class should be unresolved
+
+package a
+
+fun foo() {
+    val <!UNUSED_VARIABLE!>b<!> : <!UNRESOLVED_REFERENCE!>B<!> = <!UNRESOLVED_REFERENCE!>B<!>() //only B() is unresolved, but in ": B" and "B.foo()" B should also be unresolved
+    <!UNRESOLVED_REFERENCE!>B<!>.foo()
+
+    <!UNRESOLVED_REFERENCE!>P<!>.foo()
+
+    <!UNRESOLVED_REFERENCE!>M<!>.bar()
+}
+
+class A() {
+    class object {
+        class B() {
+            class object {
+                fun foo() {}
+            }
+        }
+
+        object P {
+            fun foo() {}
+        }
+    }
+}
+
+object N {
+    object M {
+        fun bar() {}
+    }
+}
+
+//FILE:b.kt
+package b
+
+import N.M
+import A.P
+import b.A.B
+
+fun foo() {
+    val <!UNUSED_VARIABLE!>b<!> : B = B()
+    B.foo()
+
+    P.foo()
+
+    M.bar()
+}
+
+class A() {
+    class object {
+        class B() {
+            class object {
+                fun foo() {}
+            }
+        }
+
+        object P {
+            fun foo() {}
+        }
+    }
+}
+
+object N {
+    object M {
+        fun bar() {}
+    }
+}